Korato Anniversary - Pre, Power and Phono Stage

Introduction

This is a poor review, by my standards and by the regular standard of TNT. It's poor because of a combination of factors which I'll explain, but it is interesting as it demonstrates the difficulties that system compatability, or even just changes in a reference system, can cause any reviewer.

Last year I tested two items of equipment which left me bereft when they parted. The first were the Loth-x Polaris, the second the Korato KVP10 pre-amp and KVA100 power-amp. The former were full range horns that so perfectly clicked with my system and room that at times they left me spellbound with their realism. The latter gave my IPL speakers such control and speed and imaging I could not believe the transformation - the pre-amp in particular remains the best of those I've reviewed on TNT (in my old system) and by a wide margin.

Time passed and I settled back to my own system...

Then the bike trade did well and I had some money to spend, more than ever before on hi-fi. The advantage (and one of the reasons I do it) of writing for TNT is that I could buy something I knew was good - because I'd had it in my home. The choice had to be one of the above pieces of kit. Kate (mother of my children and holder of the purse strings) loved the look of the Polaris, she also loved the Audion valve amps and thought the Koratos a bit "plain".
To be fair she also has a fine ear and though she loved the sound of the Polaris she was less sure about the Koratos and so the decision was made and at a stroke my system went one way - valve/horn rather than another muscle transistor/inefficient speakers. I'll add that the Polaris route was by far the more expensive...

Meantime I'd had a promise for some time of the first ever test of Koratos new flagship amplifiers, the Korato Anniversary pre/power and phono stage. Sadly delay followed delay...

Then a month after the arrival of the Polaris I received the Anniversaries. Now can you see the problem? A year ago I had a system, speakers in particular, perfect for them to show their abilities. Now I had 104 dbl efficient horns that with 1 watt produce ear-splitting volumes and designed with valve amps in mind as the only speakers to review a massive power amp capable of producing 160 watts per channel! Yes I could have swapped about speakers but what then to do with two wardrobe sized speakers in the meantime, i.e. a month...

But it gets worse...

Construction

The Anniversaries are instantly recognisable as being out of the same mould as their lesser siblings the KVP10 and KVA100. The chassis are similar, the main difference being that on the Anniversaries there is a second aluminium plate on either side of the logo, in this case in natural aluminium colour to contrast with the black of the main face plate, it makes them look classier, in fact despite their elevated price they still look materially good value.

Power amp

The Power amp is very similar to the KVA100 in design it's just that everything has been beefed up and component quality improved. 500VA toroids go out in favour of 800VA, the bridge rectifier goes from 25 to 35 amps, the bipolar transistors are Sanken rather than Motorola. The result is a hike from 100w to 160w, 40w being pure class "A". The binding posts are beefier (the KTA100's were pretty hefty...) and the box bigger and heavier - 29 kgs... Input sensitivity is 1.3v allowing use of passive pre's with CD players.

Pre-amp

If you read the earlier Korato test (and I strongly suggest you do) you'll see that both pre and power are fully dual mono, in the Anniversaries this runs to actually separating the two offboard power supplies for the pre into half width cases - apart from separating mains cables this is a sop to fashion rather than efficiency unless you physically separate them rather than placing them side by side. The power supply toroids go up from 50VA to 80VA.

Inside the pre's main box the amp sports a full valve stage rather than the hybrid used in the KVP10 and is completely wired with VdH SCS-18 cables. The 'upgrade' over the KVP10 includes Audio Note copper foil signal caps, Beyschlag 1W precision resistors and Black Gate caps. The preamp has no overall feedback.

Perhaps the biggest upgrade is that the Noble pot is replaced by a Alps "Black Beauty" stepped potentiometer, and this coupled with a max output of 45V is the root of many of the problems I have with the pairing.

The KVP10 came with a built-in, all-valve phono stage that I found excellent, with the Anniversaries a similar design resides in it's own full width case together with an independent, on-board, power supply. All together there are 5 boxes rather than the lesser amps 3.

For technical details lifted from Korato's site go to the end of the review.

Sound

And now the snag. Here I have an amp capable of pumping out 160w. I consider that testing the first half-watt hardly fair or even relevent. Then there's the fear of damage, a dodgy earth, or a big spike down the mains and such power could fry the speakers. So I plugged the amp into my bedroom system to check it made a sound and that's it. I'm not going to go further than to say that if it's better than the KVA100 then it's very, very good indeed, if not then Korato are loosing the plot:-)

So to the preamp...

The "old" KVP10 when matched to my Audion power amps and IPL speakers had produced a open, relatively forward presentation with bags of detail and quite amazing soundstaging and sense of atmosphere.

So I was expecting great things of the Anniversary pre. But even here that stepped attenuator caused problems. The steps were simply too large, each making a gross difference in sound level. Luckily the Audions have a volume pot each. But this had to be turned down from maximum to a 9 o'clock position in order to give the control I felt I needed. Thus another variable is put into the equation, is the volume pot on the power amp having a negative effect? My feeling is that it doesn't but I'm not happy about the situation.

So with the power amps turned down the test began.

And the result was not what I expected. The KVP10 had proved to be easily distinguishable from my Audion 'Silver Knight', in the Anniversaries case the differences were much less, in fact they were close enough for me not to be able to spot blind. I'd also not be able to say which sounded 'better' I was equally happy sitting in front of either - often an item that I couldn't spot blind, draws me into music, or just makes me want to play more of it - here both were equal.

Which makes writing the review difficult because I can't describe by differentiation, only in absolute terms.

So here goes...

In isolation the Anniversary is a fine pre-amp. It does that trick of drawing you into the music, producing all the musical clues and information without pushing detail at you. In this respect it is a classic valve amp in the positive sense of the phrase. It has an organic feel that makes some amps sound mechanical, it's smooth and liquid but can produce drama and speed when required. It also allows you to listen at very high levels without strain. All this is possible whilst still having the ability to make the hairs stand up on the back of your neck when required - Nirvanas 'Polly', Dies Irae, PJ Harvey singing just about anything etc...

Running the Audion power amps direct from a CD player and then through the Anniversary gave a similar effect to the Silver Knight as the sound became more fleshed out, less edgy with either pre, surprisingly the Anniversary being slightly the warmer of the two. Otherwise both were as transparent as you could wish.

Then to the respective phono stages and it was more of the same. They were evenly matched, producing a bold expansive soundstage, though once again the Anniversary proved just a tadge warmer.

All of which was a surprise...

You see the Korato KVP10 had proved more open and expansive than the Audion, the latter being warmer and more "easy listening", the Anniversary went the other way, so what's going on?

With such a fundamental change in speakers in the system, especially such a quantum leap in quality and philosophy (from 87 dbl transmission lines to 104 dbl horns) it's hard to make any meaningful comparison. But the horns inevitably have a more forward and revealing presentation than the IPL's and perhaps in that situation the KVP10 would be just too much of a good thing.
The Korato power amps tend to be slightly drier and have better bass control than my Audions and so the overall 'Anniversary system' balance may well be much more like the Audions. Either way I suspect (I can say no more) that the Anniversay is a better pre than the KVP10 with the kind of speaker I'm now using.

To illustrate - I am now using the Hadcock 242 on my Orbe with the Dynavector XX-2. The balance with my system with either preamp is so perfect in my home that I fear to disturb anything. Anyone who thinks that "valves can't rock", "Unipivots don't work on suspended turntables" or "horns smear bass all over the place" or any similar garbage that passes for "accepted wisdom" should pay a visit. The result at the moment is superb and the Anniversary pre doesn't screw it up which is about as much praise as I can give.

Conclusion and thoughts

I owe both Korato and TNT readers an apology for this review. Beyond saying that the amps look good, and that the pre in isolation is every bit as good as my Audio Silver Knight I can say no more. In my defence I can say it's just bad timing. However I'm unable to leave it at that and so have pressganged Steve Davey into wiring the amps into his system so in the near future you will get a proper review...

But one bit of good news comes from it all. In the original Korato review I was writing about a product that most people couldn't buy (except direct from the manufacturer), now Korato have distributors in Europe at least. All my comments on the original KVP10/KTA100 stand but now you can buy them. The Anniversaries take it all one step further, but in a slightly different direction.

Technical - from Korato's website

The Anniversary pre is constructed in three boxes: two separate dedicated power supply boxes for each channel and the third housing the audio stages of the preamp. It has five line inputs. At the time being there is no phono section. The preamplifier itself has two 5687 and two E802F valves, and each PS box has one ECL82 and one 85A2 valve.
Each channel is powered with it own 80VA toroid transformer. 10th Anniversary preamp is completely wired with VdH SCS-18 cables, has the Alps "Black Beauty" potentiometer, Audio Note copper foil signal caps, Beyschlag 1W precision resistors, Black Gate bypass capacitors, all of the connectors are gold plated with teflon insulation. The preamp has no overall feedback.